(function() {
var flag = 0, boxX = 0, boxY = 0
var onDown = function(element) {
	if (flag) {
		flag = 0
	} else {
		flag = 1
	}
	boxX = element.clientX - boxX
	boxY = element.clientY - boxY
}
var onMove = function(element) {
	var mask = Dackage.$('.mask')
	if (!flag) {
		return 0
	}
	mask.style.left = (element.clientX - boxX) + 'px'
	mask.style.top = (element.clientY - boxY) + 'px'
}
function main() {
	Dackage.$('.mask').addEventListener('mousedown', onDown)
	document.addEventListener('mousemove', onMove)
	return 0
}
if (window) {
	window.addEventListener('load', main)
}
})()